POS1111 WHAT DOES GRIP STRENGTH REFLECT IN HAND OSTEOARTHRITIS? RESULTS FROM THE DIGICOD COHORT
Authors: E. Tan, S. Tuffet, A. Rousseau, B. Fautrel, F. Rannou, F. Berenbaum, J. Sellam, A. Courties
Journal: Annals of the Rheumatic Diseases (2022)

<h3>Background</h3> Among the general population over 60 years-old, the decrease in grip strength is a marker of morbidity and mortality: its measurement during follow-up consultations is considered as a predictive marker of good health status or the patient's overall fragility (1). However, hand osteoarthritis (HOA), which can modulate grip strength and is also associated with comorbidities is never taken into account, while it is a very common disease. <h3>Objectives</h3> The objectives of this study are to describe grip strength in a symptomatic HOA population, to investigate painful osteoarthritic joints associated with decreased grip strength, and to determine whether decreased grip strength is independently associated with comorbidities in this population. <h3>Methods</h3> DIGICOD is a hospital-based observational cohort including patients with radiographic features of HOA of at least 2 joints or radiographic thumb base OA. Inflammatory rheumatism or crystal arthropathy were excluded. The data at baseline were used for the analysis. Grip strength was the higher score of 3 repeated measures using a Jamar dynamometer. Baseline grip strength of the dominant hand was compared in the cohort between men and women (Student's T test) and was described by age (by 10-year age groups using Kruskal-Wallis test). In this cross-sectional study, factors associated with a decreased grip strength were investigated using univariate and then multivariate linear regression analysis (with adjustment on age, BMI and variables with p ≤ 0.2 in univariate analysis) with stratification by sex. Results were presented by beta coefficients and their 95% confidence intervals. A first analysis focused on the association of grip strength with local factors: painful locations in the dominant hand by row and radiographic severity according to the total Kellgren-Lawrence (KL) score. The second analysis assessed the patient-level association between decreased grip strength and general characteristics, including cumulative comorbidities and markers of radio-clinical severity of hand OA, namely the AUSCAN pain score and total KL score. A sensitivity analysis was performed to look for association between grip strength and each comorbidity. <h3>Results</h3> 394 patients were analyzed, including 329 women (mean ± SD of the dominant hand's grip strength of 21.6 ± 6.9 kg) and 65 men (34.9 ± 9.8 kg) with a mean age of 66.9 ± 7.3 years. Grip strength decreased with age (p&lt;0.001) and was lower for women (p&lt;0.0001). Among women, locally, decreased grip strength was independently associated with painful involvement of at least 2 metacarpophalangeal joints (MCPs) (estimated coefficient [95% CI] -3.6 [-6.2; -1.0] kg versus no painful MCPs) but not with proximal and distal interphalangeal joints, and with a high KL total sum score (-0.06 [-0.10; -0.01] kg per additional point). At the patient-level, decreased grip strength was not associated with comorbidities but with radio-clinical severity (p&lt;0.05), i.e. a higher KL total sum score and AUSCAN pain score. Among men, neither radiographic severity nor painful locations were independently associated with a decrease of grip strength. Conversely, decreased grip strength was associated with at least 3 comorbidities (-8.5 [-15.5; -1.43] kg versus a single comorbidity being OA), independently of radiographic severity. The study of comorbidities individually did not show any particular association with grip strength. <h3>Conclusion</h3> In this cohort of symptomatic HOA, the decrease of grip strength reflects the radio-clinical severity of hand OA among women, whereas among men, it is independently associated with the accumulation of comorbidities. The presence of hand OA should be considered for further studies investigation the relationship between grip strength and morbi-mortality. <h3>References</h3> [1]Bohannon RW. Grip Strength: An Indispensable Biomarker For Older Adults. CIA. oct 2019;Volume 14:1681‑91. <h3>Disclosure of Interests</h3> None declared